RFR: 8328665: serviceability/jvmti/vthread/PopFrameTest failed with a timeout [v6]

[Chris Plummer]

On Fri, 29 Mar 2024 04:15:43 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> This PR fixes a synchronization issue in the test:
>>   `test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest`
>>   
>> The method `notifyAtBreakpoint()` can notify the `TestTask` thread when it has not reached an expected breakpoint yet.
>> The fix is to add a call to the method `ensureAtBreakpoint()` one more time in the `B2` sub-test. It is needed after the top-most frame was popped with the JVMTI `PopFrame`, and the target thread needs to reach the breakpoint again after its execution was resumed.
>> 
>> The time is very intermittent. At least, I was not able to reproduce the timeout failure in thousands of mach5 runs with the `-Xcomp` option.
>> 
>> Testing:
>>  - Run the test `test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest` thousands times in mach5
>
> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review: move log message to the right place

test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest/libPopFrameTest.cpp line 164:

> 162:       fatal(jni, "Main: ensureAtBreakpoint: waited 10 sec");
> 163:     }
> 164:     LOG("Main: ensureAtBreakpoint: waitig 100 millis\n");

Suggestion:

    LOG("Main: ensureAtBreakpoint: waiting 100 millis\n");

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PR Review Comment: https://git.openjdk.org/jdk/pull/18419#discussion_r1544769747